US government mandates have required increasing quantities of biomass-derived ethanol to be blended into transportation fuels. Due to concurrent reductions in US gasoline production and consumption, the quantity of ethanol blended into gasoline may soon exceed 10%, which may have implications for the operability of certain older vehicles not designed to utilize such fuels. Additionally, blending of increasing quantities of biomass-derived ethanol into fuels can increase the overall Reid vapor pressure to levels that exceed government mandated levels.
Thus, a need exists for new methods and systems that allow increased incorporation of biomass-derived ethanol into liquid transportation fuels, while preserving the suitability of the resulting fuel for use in most vehicles and maintaining an acceptable Reid vapor pressure of the fuel.